The invention relates to an internal combustion engine having a coolant circuit comprising a first cooling line leading to a cylinder block and a second cooling line leading to the cylinder head.
German laid-open patent application DE 100 11 143 A1 discloses a liquid-cooled internal combustion engine with a dual-circuit cooling system in which a liquid-cooled cylinder block and a separate, liquid-cooled cylinder head are connected in a coolant-conducting fashion under the control of a valve as a function of temperature by means of openings in an intermediate cylinder head gasket. One or more of the valves, which control the coolant, are bimetal valves integrated into the cylinder head gasket.
German laid-open patent applications DE 33 17 454 A1, DE 198 03 884 A1 and DE 198 03 885 A1 also disclose liquid-cooled internal combustion engines with cooling circuits in which one cooling circuit is assigned to a cylinder head and one cooling circuit is assigned to a cylinder block. The cooling circuits are connected to one another. A connection to a heat exchanger is also provided. The cooling control circuits for the cylinder head and the cylinder block are closed-loop controlled independently of one another by means of valves and a corresponding control unit.
The object of the present invention is to provide an internal combustion engine having a cooling system or coolant circuit which operates in a selectively controllable fashion.